poj 1321

#include<iostream>using namespace std;long int n,k,count;char map[10][10];bool biao[100];void DFS(int row,int num){int i;if(num==k){count++;return;}if(row>=n)return;for(i=0;i<n;i++){if(map[row][i]==1&&!biao[i]){biao[i]=true;DFS(row+1,num+1);biao[i]=false;}}DFS(row+1,num);}int main(){int i,j;while(cin>>n>>k&&n!=-1&&k!=-1){count=0;memset(biao,false,100);for(i=0;i<n;i++)for(j=0;j<n;j++)cin>>map[i][j];for(i=0;i<n;i++)for(j=0;j<n;j++){if(map[i][j]=='#')map[i][j]=1;elsemap[i][j]=0;}DFS(0,0);cout<<count<<endl;}}